This invention relates to a universal rolling mill having horizontal and vertical rolls supported by bearing chocks received in windows of a frame that includes yoke sections with adjusting members for the vertical rolls. Upper and lower pairs of crossheads are connected by nut assemblies to screwdown spindles to adjustably position the horizontal rolls. The spindles are retained against axial movement but rotatably supported by the frame. Each of the upper crossheads is constructed to swing while supported at one end by a spindle engaged with a nut assembly, thereby exposing the top portion of the frame for removal and replacement of the roll assemblies.
It is known in the art, as shown in West German Pat. Nos. 38010 and 413 914, to construct a rolling mill so that it is possible to remove an upper crosshead used to close the top of a roll housing in order to replace an exchange frame. West German Pat. No. 933 329 discloses broad-face gear units which can be swung out of the rolling line about a central axis of rotation.
U.S. Pat. No. 3,802,242 discloses a universal rolling mill stand having two upper crossheads, each connected by a pair of screwdown tie rods to one pair of bottom crossheads. The crossheads are moved toward and away from a mill frame while contacting the bearing chocks of the horizontal rolls to adjust the roll gap. The screwdown tie rods are retained by the mill frame against axial movement while interconnected with the crossheads by nut members. Outwardly-extending wing portions at each side of the mill frame carry roll-adjusting spindles to position vertical roll assemblies of the universal rolling mill.
Such a mill stand construction is compact and offers the capability of processing a wide range of structural products through scheduled roll changes. However, to replace worn rolls, it is necessary to either replace the mill stand in the processing line with a substitute mill stand or change the rolls in the mill stand while located in the processing line. In either event, lubrication and other supply lines must be disconnected and the crossheads at the top of the mill stand must be raised vertically and removed from the spindles to permit removal of the roll assemblies. After replacement roll assemblies are installed in the mill stand, two nut members in each upper crosshead must be reengaged with the threaded ends of the screwdown tie rods. This operation requires accurate handling of the crossheads while carried by a crane. The present invention is designed to eliminate such handling of the crossheads and enhances the entire rolling operation.